The invention relates to an extracting device for removing material cut during operation of a motor-operated hand tool, which is attached to the hand tool for extracting such material, the device having an extracting opening and a receiving space for receiving the cut material, which is combined together over an extracting path with an air current from the extracting opening to the receiving space, wherein a closure mechanism is provided between the extracting opening and the receiving space, having a closed position at least substantially closing the extracting path and is operated by the air current.
In an extracting device of this type, the closure device assures, that after the air current generator is switched off and independently of the orientation of the hand tool and the extracting device fastened to it, no cut material is released from the receiving space through the extracting opening.
U.S. Pat. No. 6,047,693 discloses a motor-driven cutting tool having an extracting device attached to it. The extracting device has an extracting opening, which communicates through an extracting hose with a collecting bag. When operating the cutting tool, a fan generates a suction current from the extracting opening to the collecting bag. When this is done an elastic, disklike closure element that completely blocks the open flow cross-section of the extracting hose, is partially opened by deflection in the direction of the collection bag. After the fan is switched off, the relaxing collection bag releases into the extracting hose an airflow opposite to the extracting current in the direction of the extracting opening, whereby the closure element is urged against an annular stop and thereby blocks the collecting bag from the extracting opening.
This type of closure device is relatively prone to malfunction. Accordingly, it frequently happens that when the fan is switched off, extracted material becomes stuck between the closure element and the stop and complete closing of the closure device is prevented. In addition, it is also possible that over time the closure element is permanently deformed, whereby incomplete closing can result. In addition, by virtue of the opening of the closure element, turbulence is produced in the extracting hose, which results in clear flow losses and reduced extracting performance.